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Type I interferon signaling in hematopoietic cells is required for survival in mouse polymicrobial sepsis by regulating CXCL10.

Kelly-Scumpia KM, Scumpia PO, Delano MJ, Weinstein JS, Cuenca AG, Wynn JL, Moldawer LL - J. Exp. Med. (2010)

Bottom Line: During endotoxicosis or highly lethal bacterial infections where systemic inflammation predominates, mice deficient in IFN-alpha/beta receptor (IFNAR) display decreased systemic inflammation and improved outcome.This was not associated with an altered early systemic inflammatory response, except for decreased CXCL10 production.IFNAR(-/-) mice display persistently elevated peritoneal bacterial counts compared with wild-type mice, reduced peritoneal neutrophil recruitment, and recruitment of neutrophils with poor phagocytic function despite normal to enhanced adaptive immune function during sepsis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department Surgery, University of Florida College of Medicine, Gainesville, FL 32610, USA.

ABSTRACT
Type I interferon (IFN) alpha/beta is critical for host defense. During endotoxicosis or highly lethal bacterial infections where systemic inflammation predominates, mice deficient in IFN-alpha/beta receptor (IFNAR) display decreased systemic inflammation and improved outcome. However, human sepsis mortality often occurs during a prolonged period of immunosuppression and not from exaggerated inflammation. We used a low lethality cecal ligation and puncture (CLP) model of sepsis to determine the role of type I IFNs in host defense during sepsis. Despite increased endotoxin resistance, IFNAR(-/-) and chimeric mice lacking IFNAR in hematopoietic cells display increased mortality to CLP. This was not associated with an altered early systemic inflammatory response, except for decreased CXCL10 production. IFNAR(-/-) mice display persistently elevated peritoneal bacterial counts compared with wild-type mice, reduced peritoneal neutrophil recruitment, and recruitment of neutrophils with poor phagocytic function despite normal to enhanced adaptive immune function during sepsis. Importantly, CXCL10 treatment of IFNAR(-/-) mice improves survival and decreases peritoneal bacterial loads, and CXCL10 increases mouse and human neutrophil phagocytosis. Using a low lethality sepsis model, we identify a critical role of type I IFN-dependent CXCL10 in host defense during polymicrobial sepsis by increasing neutrophil recruitment and function.

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CXCL10 treatment improves human neutrophil phagocytic function in vitro. Whole-blood leukocytes were collected using Histopaque 1119. 105 unstimulated cells, cells treated with 100 ng CXCL10 for 4 or 2 h followed by an 18-h stimulation with 1 µg/ml LPS, or cells stimulated with LPS alone for 18 h were plated in round-bottom 96-well plates. FITC beads were added and cells were incubated at 37°C for 30 min. Cells were washed and stained for neutrophil markers (CD66b+CD16hi). (A) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top) or CXCL10 treatment for 4 h (bottom). (B) Graphical analysis of the percentage of phagocytic neutrophils from one healthy control (P = 0.019 using the Student’s t test). (C) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top), LPS-stimulated (middle), and CXCL10-treated + LPS-treated leukocytes (bottom). (D) Graph of the percentage of phagocytic neutrophils from one healthy control (P < 0.001 using one-way ANOVA). For all panels, treatment was performed in triplicate and the experiment was performed on three healthy controls with similar results. Error bars indicate SD.
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fig6: CXCL10 treatment improves human neutrophil phagocytic function in vitro. Whole-blood leukocytes were collected using Histopaque 1119. 105 unstimulated cells, cells treated with 100 ng CXCL10 for 4 or 2 h followed by an 18-h stimulation with 1 µg/ml LPS, or cells stimulated with LPS alone for 18 h were plated in round-bottom 96-well plates. FITC beads were added and cells were incubated at 37°C for 30 min. Cells were washed and stained for neutrophil markers (CD66b+CD16hi). (A) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top) or CXCL10 treatment for 4 h (bottom). (B) Graphical analysis of the percentage of phagocytic neutrophils from one healthy control (P = 0.019 using the Student’s t test). (C) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top), LPS-stimulated (middle), and CXCL10-treated + LPS-treated leukocytes (bottom). (D) Graph of the percentage of phagocytic neutrophils from one healthy control (P < 0.001 using one-way ANOVA). For all panels, treatment was performed in triplicate and the experiment was performed on three healthy controls with similar results. Error bars indicate SD.

Mentions: Septic adult peripheral blood neutrophils demonstrate reduced phagocytic activity during sepsis (Kaufmann et al., 2006; Danikas et al., 2008; Taneja et al., 2008). Although no human studies have examined whether type I IFN is increased in sepsis, CXCL10 was shown to be an early marker of sepsis in neonates and adults. Whether CXCL10 mediates neutrophil phagocytosis in humans, or whether levels during sepsis are sufficient or sustained long enough to mediate adequate neutrophil recruitment and phagocytic activity is unknown. In this report, we find that although human blood neutrophils (CD66b+CD16hi cells) have a low phagocytic activity, treatment for 4 h with CXCL10 doubles their phagocytic ability (Fig. 6 A). Furthermore, treatment with CXCL10 for 2 h improves LPS-mediated neutrophil phagocytosis (P < 0.001 using one-way ANOVA; Fig. 6 B). These data suggest that CXCL10 treatment may improve neutrophil phagocytosis in sepsis.


Type I interferon signaling in hematopoietic cells is required for survival in mouse polymicrobial sepsis by regulating CXCL10.

Kelly-Scumpia KM, Scumpia PO, Delano MJ, Weinstein JS, Cuenca AG, Wynn JL, Moldawer LL - J. Exp. Med. (2010)

CXCL10 treatment improves human neutrophil phagocytic function in vitro. Whole-blood leukocytes were collected using Histopaque 1119. 105 unstimulated cells, cells treated with 100 ng CXCL10 for 4 or 2 h followed by an 18-h stimulation with 1 µg/ml LPS, or cells stimulated with LPS alone for 18 h were plated in round-bottom 96-well plates. FITC beads were added and cells were incubated at 37°C for 30 min. Cells were washed and stained for neutrophil markers (CD66b+CD16hi). (A) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top) or CXCL10 treatment for 4 h (bottom). (B) Graphical analysis of the percentage of phagocytic neutrophils from one healthy control (P = 0.019 using the Student’s t test). (C) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top), LPS-stimulated (middle), and CXCL10-treated + LPS-treated leukocytes (bottom). (D) Graph of the percentage of phagocytic neutrophils from one healthy control (P < 0.001 using one-way ANOVA). For all panels, treatment was performed in triplicate and the experiment was performed on three healthy controls with similar results. Error bars indicate SD.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2822595&req=5

fig6: CXCL10 treatment improves human neutrophil phagocytic function in vitro. Whole-blood leukocytes were collected using Histopaque 1119. 105 unstimulated cells, cells treated with 100 ng CXCL10 for 4 or 2 h followed by an 18-h stimulation with 1 µg/ml LPS, or cells stimulated with LPS alone for 18 h were plated in round-bottom 96-well plates. FITC beads were added and cells were incubated at 37°C for 30 min. Cells were washed and stained for neutrophil markers (CD66b+CD16hi). (A) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top) or CXCL10 treatment for 4 h (bottom). (B) Graphical analysis of the percentage of phagocytic neutrophils from one healthy control (P = 0.019 using the Student’s t test). (C) Representative histograms of the percentage of phagocytic neutrophils from unstimulated (top), LPS-stimulated (middle), and CXCL10-treated + LPS-treated leukocytes (bottom). (D) Graph of the percentage of phagocytic neutrophils from one healthy control (P < 0.001 using one-way ANOVA). For all panels, treatment was performed in triplicate and the experiment was performed on three healthy controls with similar results. Error bars indicate SD.
Mentions: Septic adult peripheral blood neutrophils demonstrate reduced phagocytic activity during sepsis (Kaufmann et al., 2006; Danikas et al., 2008; Taneja et al., 2008). Although no human studies have examined whether type I IFN is increased in sepsis, CXCL10 was shown to be an early marker of sepsis in neonates and adults. Whether CXCL10 mediates neutrophil phagocytosis in humans, or whether levels during sepsis are sufficient or sustained long enough to mediate adequate neutrophil recruitment and phagocytic activity is unknown. In this report, we find that although human blood neutrophils (CD66b+CD16hi cells) have a low phagocytic activity, treatment for 4 h with CXCL10 doubles their phagocytic ability (Fig. 6 A). Furthermore, treatment with CXCL10 for 2 h improves LPS-mediated neutrophil phagocytosis (P < 0.001 using one-way ANOVA; Fig. 6 B). These data suggest that CXCL10 treatment may improve neutrophil phagocytosis in sepsis.

Bottom Line: During endotoxicosis or highly lethal bacterial infections where systemic inflammation predominates, mice deficient in IFN-alpha/beta receptor (IFNAR) display decreased systemic inflammation and improved outcome.This was not associated with an altered early systemic inflammatory response, except for decreased CXCL10 production.IFNAR(-/-) mice display persistently elevated peritoneal bacterial counts compared with wild-type mice, reduced peritoneal neutrophil recruitment, and recruitment of neutrophils with poor phagocytic function despite normal to enhanced adaptive immune function during sepsis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department Surgery, University of Florida College of Medicine, Gainesville, FL 32610, USA.

ABSTRACT
Type I interferon (IFN) alpha/beta is critical for host defense. During endotoxicosis or highly lethal bacterial infections where systemic inflammation predominates, mice deficient in IFN-alpha/beta receptor (IFNAR) display decreased systemic inflammation and improved outcome. However, human sepsis mortality often occurs during a prolonged period of immunosuppression and not from exaggerated inflammation. We used a low lethality cecal ligation and puncture (CLP) model of sepsis to determine the role of type I IFNs in host defense during sepsis. Despite increased endotoxin resistance, IFNAR(-/-) and chimeric mice lacking IFNAR in hematopoietic cells display increased mortality to CLP. This was not associated with an altered early systemic inflammatory response, except for decreased CXCL10 production. IFNAR(-/-) mice display persistently elevated peritoneal bacterial counts compared with wild-type mice, reduced peritoneal neutrophil recruitment, and recruitment of neutrophils with poor phagocytic function despite normal to enhanced adaptive immune function during sepsis. Importantly, CXCL10 treatment of IFNAR(-/-) mice improves survival and decreases peritoneal bacterial loads, and CXCL10 increases mouse and human neutrophil phagocytosis. Using a low lethality sepsis model, we identify a critical role of type I IFN-dependent CXCL10 in host defense during polymicrobial sepsis by increasing neutrophil recruitment and function.

Show MeSH
Related in: MedlinePlus