Issue 19, 2019

Nanoscale distribution of TLR4 on primary human macrophages stimulated with LPS and ATI

Abstract

Toll-like receptor 4 (TLR4) plays a crucial role in the recognition of invading pathogens. Upon activation by lipopolysaccharides (LPS), TLR4 is recruited into specific membrane domains and dimerizes. In addition to LPS, TLR4 can be stimulated by wheat amylase-trypsin inhibitors (ATI). ATI are proteins associated with gluten containing grains, whose ingestion promotes intestinal and extraintestinal inflammation. However, the effect of ATI vs. LPS on the membrane distribution of TLR4 at the nanoscale has not been analyzed. In this study, we investigated the effect of LPS and ATI stimulation on the membrane distribution of TLR4 in primary human macrophages using single molecule localization microscopy (SMLM). We found that in unstimulated macrophages the majority of TLR4 molecules are located in clusters, but with donor-dependent variations from ∼51% to ∼75%. Depending on pre-clustering, we found pronounced variations in the fraction of clustered molecules and density of clusters on the membrane upon LPS and ATI stimulation. Although clustering differed greatly among the human donors, we found an almost constant cluster diameter of ∼44 nm for all donors, independent of treatment. Together, our results show donor-dependent but comparable effects between ATI and LPS stimulation on the membrane distribution of TLR4. This may indicate a general mechanism of TLR4 activation in primary human macrophages. Furthermore, our methodology visualizes TLR4 receptor clustering and underlines its functional role as a signaling platform.

Graphical abstract: Nanoscale distribution of TLR4 on primary human macrophages stimulated with LPS and ATI

Supplementary files

Article information

Article type
Paper
Submitted
29 Jan 2019
Accepted
27 Apr 2019
First published
30 Apr 2019
This article is Open Access
Creative Commons BY license

Nanoscale, 2019,11, 9769-9779

Nanoscale distribution of TLR4 on primary human macrophages stimulated with LPS and ATI

J. Neumann, K. Ziegler, M. Gelléri, J. Fröhlich-Nowoisky, F. Liu, I. Bellinghausen, D. Schuppan, U. Birk, U. Pöschl, C. Cremer and K. Lucas, Nanoscale, 2019, 11, 9769 DOI: 10.1039/C9NR00943D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements