Phagocytosis inhibits F-actin-enriched membrane protrusions stimulated by fractalkine (CX3CL1) and colony-stimulating factor 1

Yong Luo, Beth M. Isaac, Arturo Casadevall, Dianne Cox

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Cryptococcus neoformans is the only encapsulated human-pathogenic fungus and a facultative intracellular pathogen that can reside in macrophages without host cell lysis. In the present study, we investigated how phagocytosis of C. neoformans affected the macrophage response to chemoattractants such as fractalkine (FKN) (CX3CL1) and colony-stimulating factor 1 (CSF-1). Phagocytosis of immunoglobulin G (IgG)-opsonized C. neoformans and IgG- or C3bi-opsonized sheep erythrocytes was performed using a RAW 264.7 subline (LR5 cells) and bone marrow-derived macrophages (BMM). The chemotactic response to FKN or CSF-1 was quantitated by measurement of the formation of F-actin-enriched membrane protrusions (ruffles), which showed that FKN or CSF-1 stimulated strong transient ruffling in both LR5 cells and BMM. This stimulated cell ruffling was inhibited by phagocytosis in an intracellular-pathogen-number-dependent manner. The inhibition of ruffling was not simply a result of reduced membrane availability since membrane sequestration by sucrose treatment did not inhibit the ruffling response. The phagocytosis process was required to inhibit ruffling as BMM from FcγR-/- mice that bound C. neoformans but did not ingest it retained the ability to ruffle in response to chemoattractants. These results imply that the inhibition of FKN- or CSF-1-stimulated cell ruffling was a direct consequence of the phagocytosis process. Since cell ruffling is a prelude to chemotaxis, this observation links two functions of macrophages that are critical to host defense, chemotaxis and phagocytosis. Phagocytosis-induced chemotactic suppression may enhance host defense by keeping these antimicrobial effector cells at infected sites and reduce the likelihood of microbial spread by wandering macrophages containing infectious cargo.

Original languageEnglish (US)
Pages (from-to)4487-4495
Number of pages9
JournalInfection and Immunity
Volume77
Issue number10
DOIs
StatePublished - Oct 2009

Fingerprint

Chemokine CX3CL1
Macrophage Colony-Stimulating Factor
Phagocytosis
Actins
Macrophages
Cryptococcus neoformans
Membranes
Chemotactic Factors
Chemotaxis
Immunoglobulin G
Complement C3b
Aptitude
Sucrose
Sheep
Fungi
Erythrocytes

ASJC Scopus subject areas

  • Immunology
  • Microbiology
  • Parasitology
  • Infectious Diseases

Cite this

Phagocytosis inhibits F-actin-enriched membrane protrusions stimulated by fractalkine (CX3CL1) and colony-stimulating factor 1. / Luo, Yong; Isaac, Beth M.; Casadevall, Arturo; Cox, Dianne.

In: Infection and Immunity, Vol. 77, No. 10, 10.2009, p. 4487-4495.

Research output: Contribution to journalArticle

@article{49dd5c695f3846eba6178bba2c2744a5,
title = "Phagocytosis inhibits F-actin-enriched membrane protrusions stimulated by fractalkine (CX3CL1) and colony-stimulating factor 1",
abstract = "Cryptococcus neoformans is the only encapsulated human-pathogenic fungus and a facultative intracellular pathogen that can reside in macrophages without host cell lysis. In the present study, we investigated how phagocytosis of C. neoformans affected the macrophage response to chemoattractants such as fractalkine (FKN) (CX3CL1) and colony-stimulating factor 1 (CSF-1). Phagocytosis of immunoglobulin G (IgG)-opsonized C. neoformans and IgG- or C3bi-opsonized sheep erythrocytes was performed using a RAW 264.7 subline (LR5 cells) and bone marrow-derived macrophages (BMM). The chemotactic response to FKN or CSF-1 was quantitated by measurement of the formation of F-actin-enriched membrane protrusions (ruffles), which showed that FKN or CSF-1 stimulated strong transient ruffling in both LR5 cells and BMM. This stimulated cell ruffling was inhibited by phagocytosis in an intracellular-pathogen-number-dependent manner. The inhibition of ruffling was not simply a result of reduced membrane availability since membrane sequestration by sucrose treatment did not inhibit the ruffling response. The phagocytosis process was required to inhibit ruffling as BMM from FcγR-/- mice that bound C. neoformans but did not ingest it retained the ability to ruffle in response to chemoattractants. These results imply that the inhibition of FKN- or CSF-1-stimulated cell ruffling was a direct consequence of the phagocytosis process. Since cell ruffling is a prelude to chemotaxis, this observation links two functions of macrophages that are critical to host defense, chemotaxis and phagocytosis. Phagocytosis-induced chemotactic suppression may enhance host defense by keeping these antimicrobial effector cells at infected sites and reduce the likelihood of microbial spread by wandering macrophages containing infectious cargo.",
author = "Yong Luo and Isaac, {Beth M.} and Arturo Casadevall and Dianne Cox",
year = "2009",
month = "10",
doi = "10.1128/IAI.00530-09",
language = "English (US)",
volume = "77",
pages = "4487--4495",
journal = "Infection and Immunity",
issn = "0019-9567",
publisher = "American Society for Microbiology",
number = "10",

}

TY - JOUR

T1 - Phagocytosis inhibits F-actin-enriched membrane protrusions stimulated by fractalkine (CX3CL1) and colony-stimulating factor 1

AU - Luo, Yong

AU - Isaac, Beth M.

AU - Casadevall, Arturo

AU - Cox, Dianne

PY - 2009/10

Y1 - 2009/10

N2 - Cryptococcus neoformans is the only encapsulated human-pathogenic fungus and a facultative intracellular pathogen that can reside in macrophages without host cell lysis. In the present study, we investigated how phagocytosis of C. neoformans affected the macrophage response to chemoattractants such as fractalkine (FKN) (CX3CL1) and colony-stimulating factor 1 (CSF-1). Phagocytosis of immunoglobulin G (IgG)-opsonized C. neoformans and IgG- or C3bi-opsonized sheep erythrocytes was performed using a RAW 264.7 subline (LR5 cells) and bone marrow-derived macrophages (BMM). The chemotactic response to FKN or CSF-1 was quantitated by measurement of the formation of F-actin-enriched membrane protrusions (ruffles), which showed that FKN or CSF-1 stimulated strong transient ruffling in both LR5 cells and BMM. This stimulated cell ruffling was inhibited by phagocytosis in an intracellular-pathogen-number-dependent manner. The inhibition of ruffling was not simply a result of reduced membrane availability since membrane sequestration by sucrose treatment did not inhibit the ruffling response. The phagocytosis process was required to inhibit ruffling as BMM from FcγR-/- mice that bound C. neoformans but did not ingest it retained the ability to ruffle in response to chemoattractants. These results imply that the inhibition of FKN- or CSF-1-stimulated cell ruffling was a direct consequence of the phagocytosis process. Since cell ruffling is a prelude to chemotaxis, this observation links two functions of macrophages that are critical to host defense, chemotaxis and phagocytosis. Phagocytosis-induced chemotactic suppression may enhance host defense by keeping these antimicrobial effector cells at infected sites and reduce the likelihood of microbial spread by wandering macrophages containing infectious cargo.

AB - Cryptococcus neoformans is the only encapsulated human-pathogenic fungus and a facultative intracellular pathogen that can reside in macrophages without host cell lysis. In the present study, we investigated how phagocytosis of C. neoformans affected the macrophage response to chemoattractants such as fractalkine (FKN) (CX3CL1) and colony-stimulating factor 1 (CSF-1). Phagocytosis of immunoglobulin G (IgG)-opsonized C. neoformans and IgG- or C3bi-opsonized sheep erythrocytes was performed using a RAW 264.7 subline (LR5 cells) and bone marrow-derived macrophages (BMM). The chemotactic response to FKN or CSF-1 was quantitated by measurement of the formation of F-actin-enriched membrane protrusions (ruffles), which showed that FKN or CSF-1 stimulated strong transient ruffling in both LR5 cells and BMM. This stimulated cell ruffling was inhibited by phagocytosis in an intracellular-pathogen-number-dependent manner. The inhibition of ruffling was not simply a result of reduced membrane availability since membrane sequestration by sucrose treatment did not inhibit the ruffling response. The phagocytosis process was required to inhibit ruffling as BMM from FcγR-/- mice that bound C. neoformans but did not ingest it retained the ability to ruffle in response to chemoattractants. These results imply that the inhibition of FKN- or CSF-1-stimulated cell ruffling was a direct consequence of the phagocytosis process. Since cell ruffling is a prelude to chemotaxis, this observation links two functions of macrophages that are critical to host defense, chemotaxis and phagocytosis. Phagocytosis-induced chemotactic suppression may enhance host defense by keeping these antimicrobial effector cells at infected sites and reduce the likelihood of microbial spread by wandering macrophages containing infectious cargo.

UR - http://www.scopus.com/inward/record.url?scp=70349420953&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70349420953&partnerID=8YFLogxK

U2 - 10.1128/IAI.00530-09

DO - 10.1128/IAI.00530-09

M3 - Article

C2 - 19620351

AN - SCOPUS:70349420953

VL - 77

SP - 4487

EP - 4495

JO - Infection and Immunity

JF - Infection and Immunity

SN - 0019-9567

IS - 10

ER -