An Assay for TLR-Dependent NF-кB/AP-1 Transcription Factor Signaling in Macrophages

Published: January 31, 2024

Abstract

Source: McKiel, L. A., et al. A Macrophage Reporter Cell Assay to Examine Toll-Like Receptor-Mediated NF-kB/AP-1 Signaling on Adsorbed Protein Layers on Polymeric Surfaces. J. Vis. Exp. (2020).

This video demonstrates an assay to examine the toll-like receptor(TLR)-dependent activity of the transcription factors nuclear factor-kappa-B (NF-κB) and activator protein-1 (AP-1) in macrophages. The TLRs trigger a pro-inflammatory signaling cascade upon recognizing damage-associated molecular patterns (DAMPs), activating NF-κB and AP-1. The engineered reporter macrophages produce secreted embryonic alkaline phosphatase (SEAP) enzyme upon NF-κB and AP-1 activation, which is detected via a chromogenic reaction.

Protocol

1. Media and Reagent Preparation Prepare fibroblast media. Combine 450 mL of Dulbecco's modified Eagle medium (DMEM), 50 mL of fetal bovine serum (FBS), and 5 mL of penicillin/streptomycin. Store at 4 °C for up to 3 months. Prepare reporter macrophage growth media in 50 mL aliquots. Combine 45 mL of DMEM, 5 mL of FBS, 5 μg/mL mycoplasma elimination reagent (Table of Materials), and 200 μg/mL phleomycin D1 (Table of Materials). Sto…

Representative Results

Figure 1: Methods and results for the alkaline phosphatase assay of NF-кB/AP-1 reporter macrophages on TCPS, PMMA, PDMS, and fPTFE. (A) Diagram of the workflow for the reporter macrophage alkaline phosphatase assay. (B) Western blot of lysate confirming the presence of DAMP species HMGB1 and HSP60, with β-actin as the loading control. (C</stron…

Offenlegungen

The authors have nothing to disclose.

Materials

Cell culture reagents
anti-mouse/human CD282 (TLR2) Biolegend 121802
CLI-095 (TLR4 inhibitor) Invivogen TLRL-CLI95
C57 complement plasma K2 EDTA 10ml, innovative grade US origin InnovativeResearch IGMSC57-K2 EDTA-Compl-10ml Mouse plasma
Dulbecco's modified eagle medium (DMEM) Sigma Aldrich D6429-500ML
Dulbecco's phosphate buffered saline (DPBS) Fisher Scientific 14190250 No calcium, no magnesium
Fetal bovine serum (FBS), research grade Wisent 98150
LPS-EK Invivogen TLRL-EKLPS Lipopolysaccharide from Escherichia coli K12
NIH/3T3 fibroblasts ATCC CRL-1658
Pam3CSK4 Invivogen tlrl-pms Synthetic triacylated lipopeptide – TLR1/2 ligand
Penicillin/streptomycin Sigma Aldrich P4333-100ML
Plasmocin Invivogen ANT-MPP Mycoplasma elimination reagent
RAW-Blue cells Invivogen raw-sp NF-κB/AP-1 reporter macrophage cell line
Trypan blue solution, 0.4% Fisher Scientific 15250061
TrypLE express enzyme (1X) Fisher Scientific 12604021 animal origin-free recombinant cell dissociation enzyme
Zeocin Invivogen ANT-ZN-1
Kits and assays
ELISA precoated plates, mouse IL-6 Biolegend B213022
ELISA precoated plates, mouse TNF-α Biolegend B220233
Endotoxin (Escherichia coli) – Control standard endotoxin (CSE) Associates of Cape Cope Inc. E0005-5 Endotoxin for standard curve in chromogenic endotoxin assay
LAL water, 100 mL Associates of Cape Cope Inc. WP1001 Used with chromogenic endotoxin assay
Micro BCA protein assay Fisher Scientific PI23235
Limulus amebocyte lysate (LAL) Pyrochrome endotoxin test kit Associates of Cape Cope Inc. C1500-5 Chromogenic endotoxin assay reagent
QUANTI-Blue alkaline phosphatase detection medium Invivogen rep-qb2 Alkaline phosphatase assay to indirectly measure NF-κB/AP-1 activity
Polymeric coating reagents
Chloroform, anhydrous Sigma Aldrich 288306-1L
Ethyl alcohol anhydrous Commercial Alcohols P006EAAN Sigma: Reagent alcohol, anhydrous, 676829-1L
Straight tapered fine tip forceps Fisher Scientific 16-100-113
Fluorinert FC-40 solvent Sigma Aldrich F9755-100ML Fluorinated solvent for fPTFE
Cell culture grade water (endotoxin-free) Fisher Scientific SH30529LS
Poly(methyl methacrylate) (PMMA) Sigma Aldrich 182230-25G
Sylgard 184 elastomer kit Fisher Scientific 50822180
Teflon-AF (fPTFE) Sigma Aldrich 469610-1G Poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene]
Consumables
Adhesive plate seals Fisher Scientific AB-0580
Axygen microtubes, 1.5 mL Fisher Scientific 14-222-155
Borosilicate glass scintillation vials, with white polypropylene caps Fisher Scientific 03-337-4
Clear PS 48-well plate Fisher Scientific 08-772-52
Clear TCPS 96-well plate Fisher Scientific 08-772-2C
Clear TCPS 48-well plate Fisher Scientific 08-772-1C
Cover glasses, circles Fisher Scientific 12-545-81
Falcon tissue culture treated flasks, T25 Fisher Scientific 10-126-10
sticky-Slide 8 Well Ibidi 80828
Superfrost microscope slides Fisher Scientific 12-550-15
Tissue culture treated flasks, T150 Fisher Scientific 08-772-48

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An Assay for TLR-Dependent NF-&kcy;B/AP-1 Transcription Factor Signaling in Macrophages. J. Vis. Exp. (Pending Publication), e21916, doi: (2024).

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