Bone components downregulate expression of toll-like receptor 4 on the surface of human monocytic U937 cells

A cell model for postfracture immune dysfunction

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

To mimic the immune status of monocyte in the localized fracture region, toll-like receptor 4 (TLR4) surface expression in human monocytic U937 cells was used as the main target to assess immune dysfunction following bone component exposure. We first identified the effects of bone components (including the marrow content) on TLR4 surface expression and then examined the mechanisms underlying the changes. The level of microRNA-146a expression, an indicator of endotoxin tolerance, was also assayed. Bone component exposure downregulated TLR4 surface expression at 24 h by flow cytometry analysis, compatible with the result obtained from the membranous portion of TLR4 by western blot analysis. The cytoplasmic portion of TLR4 paradoxically increased after bone component exposure. Impaired TLR4 trafficking from the cytoplasm to the membrane was related to gp96 downregulation, as observed by western blot analysis, and this was further evidenced by gp96-TLR4 colocalization under confocal microscopy. TaqMan analysis revealed that the expression of microRNA-146a was also upregulated. This cell model demonstrated that bone component exposure downregulated TLR4 surface expression in a gp96-related manner in human monocytic U937 cells, an indicator of immunosuppression at 24 h. Immune dysfunction was further evidenced by upregulation of microRNA-146a expression at the same time point.

Original languageEnglish
Article number896576
JournalMediators of Inflammation
Volume2015
DOIs
Publication statusPublished - 2015

Fingerprint

U937 Cells
Toll-Like Receptor 4
Down-Regulation
Bone and Bones
MicroRNAs
Western Blotting
Confocal Microscopy
Endotoxins
Immunosuppression
Monocytes
Flow Cytometry
Cytoplasm
Up-Regulation
Bone Marrow
Membranes

ASJC Scopus subject areas

  • Immunology
  • Cell Biology

Cite this

@article{96fa75a469034a6a84ae6c042843bbce,
title = "Bone components downregulate expression of toll-like receptor 4 on the surface of human monocytic U937 cells: A cell model for postfracture immune dysfunction",
abstract = "To mimic the immune status of monocyte in the localized fracture region, toll-like receptor 4 (TLR4) surface expression in human monocytic U937 cells was used as the main target to assess immune dysfunction following bone component exposure. We first identified the effects of bone components (including the marrow content) on TLR4 surface expression and then examined the mechanisms underlying the changes. The level of microRNA-146a expression, an indicator of endotoxin tolerance, was also assayed. Bone component exposure downregulated TLR4 surface expression at 24 h by flow cytometry analysis, compatible with the result obtained from the membranous portion of TLR4 by western blot analysis. The cytoplasmic portion of TLR4 paradoxically increased after bone component exposure. Impaired TLR4 trafficking from the cytoplasm to the membrane was related to gp96 downregulation, as observed by western blot analysis, and this was further evidenced by gp96-TLR4 colocalization under confocal microscopy. TaqMan analysis revealed that the expression of microRNA-146a was also upregulated. This cell model demonstrated that bone component exposure downregulated TLR4 surface expression in a gp96-related manner in human monocytic U937 cells, an indicator of immunosuppression at 24 h. Immune dysfunction was further evidenced by upregulation of microRNA-146a expression at the same time point.",
author = "Jui-An Lin and Feng-Yen Lin and Ta-Liang Chen",
year = "2015",
doi = "10.1155/2015/896576",
language = "English",
volume = "2015",
journal = "Mediators of Inflammation",
issn = "0962-9351",
publisher = "Hindawi Publishing Corporation",

}

TY - JOUR

T1 - Bone components downregulate expression of toll-like receptor 4 on the surface of human monocytic U937 cells

T2 - A cell model for postfracture immune dysfunction

AU - Lin, Jui-An

AU - Lin, Feng-Yen

AU - Chen, Ta-Liang

PY - 2015

Y1 - 2015

N2 - To mimic the immune status of monocyte in the localized fracture region, toll-like receptor 4 (TLR4) surface expression in human monocytic U937 cells was used as the main target to assess immune dysfunction following bone component exposure. We first identified the effects of bone components (including the marrow content) on TLR4 surface expression and then examined the mechanisms underlying the changes. The level of microRNA-146a expression, an indicator of endotoxin tolerance, was also assayed. Bone component exposure downregulated TLR4 surface expression at 24 h by flow cytometry analysis, compatible with the result obtained from the membranous portion of TLR4 by western blot analysis. The cytoplasmic portion of TLR4 paradoxically increased after bone component exposure. Impaired TLR4 trafficking from the cytoplasm to the membrane was related to gp96 downregulation, as observed by western blot analysis, and this was further evidenced by gp96-TLR4 colocalization under confocal microscopy. TaqMan analysis revealed that the expression of microRNA-146a was also upregulated. This cell model demonstrated that bone component exposure downregulated TLR4 surface expression in a gp96-related manner in human monocytic U937 cells, an indicator of immunosuppression at 24 h. Immune dysfunction was further evidenced by upregulation of microRNA-146a expression at the same time point.

AB - To mimic the immune status of monocyte in the localized fracture region, toll-like receptor 4 (TLR4) surface expression in human monocytic U937 cells was used as the main target to assess immune dysfunction following bone component exposure. We first identified the effects of bone components (including the marrow content) on TLR4 surface expression and then examined the mechanisms underlying the changes. The level of microRNA-146a expression, an indicator of endotoxin tolerance, was also assayed. Bone component exposure downregulated TLR4 surface expression at 24 h by flow cytometry analysis, compatible with the result obtained from the membranous portion of TLR4 by western blot analysis. The cytoplasmic portion of TLR4 paradoxically increased after bone component exposure. Impaired TLR4 trafficking from the cytoplasm to the membrane was related to gp96 downregulation, as observed by western blot analysis, and this was further evidenced by gp96-TLR4 colocalization under confocal microscopy. TaqMan analysis revealed that the expression of microRNA-146a was also upregulated. This cell model demonstrated that bone component exposure downregulated TLR4 surface expression in a gp96-related manner in human monocytic U937 cells, an indicator of immunosuppression at 24 h. Immune dysfunction was further evidenced by upregulation of microRNA-146a expression at the same time point.

UR - http://www.scopus.com/inward/record.url?scp=84939126894&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84939126894&partnerID=8YFLogxK

U2 - 10.1155/2015/896576

DO - 10.1155/2015/896576

M3 - Article

VL - 2015

JO - Mediators of Inflammation

JF - Mediators of Inflammation

SN - 0962-9351

M1 - 896576

ER -