Brefeldin A

Inhibitor of STING trafficking

Inhibition of intracellular protein trafficking by Brefeldin A

Brefeldin A (BFA) is a fungal macrocyclic lactone and a potent, reversible inhibitor of intracellular vesicle formation and protein trafficking between the endoplasmic reticulum (ER) and the Golgi apparatus [1]. BFA and its analogs are promising inhibitors in drug development due to a number of key features such as apoptosis‑inducing properties as well as antitumor, antifungal, and antiviral effects [2]. Interestingly, despite effectively impairing NLRP3 inflammasome activation, BFA does not block the release of IL-1β, for which the secretion mechanism remains elusive [3].

Mode of action:

The blocking of intracellular vesicle movement in BFA-treated cells causes the rapid accumulation of proteins in the ER, thereby disrupting the trafficking of many proteins. Hence, BFA is commonly utilized as an inhibitor of protein secretion in cellular assays. 

BFA also effectively inhibits the secretion of cytokines by blocking the trafficking of upstream signaling proteins. BFA inhibits type I interferon (IFN) production by blocking the dissociation of activated STING (stimulator of interferon genes) from the ER. This prevents the movement of STING to the ER-Golgi intermediate compartment (ERGIC), where it activates the TBK1-IRF3 signaling axis, and ultimately triggers the expression of IFNs [4]. 

Key Features of Brefeldin A:

• Brefeldin A is a potent inhibitor of protein trafficking from the ER to the Golgi apparatus.
• Brefeldin A inhibits the translocation of STING to the ERGIC, thereby blocking STING-induced type I IFN production.
• InvitroFit™: each lot of Brefeldin A is highly pure (≥95%) and functionally tested.

References:

1. Chardin, P. & McCormick, F. 1999. Brefeldin A: the advantage of being uncompetitive. Cell 97, 153-155.
2. Paek, S. M. 2018. Recent Synthesis and Discovery of Brefeldin A Analogs. Mar Drugs 16.
3. Hong, S. et al., 2019. Brefeldin A-sensitive ER-Golgi vesicle trafficking contributes to NLRP3-dependent caspase-1 activation. FASEB J 33, 4547-4558. 
4. Dobbs, N. et al., 2015. STING Activation by Translocation from the ER Is Associated with Infection and Autoinflammatory Disease. Cell Host Microbe 18, 157-168. 

Figures

Brefeldin A inhibits STING-induced IRF activity in THP1-Dual™ cells: The cells were incubated in the presence or absence of increasing concentrations of Brefeldin A (0 - 10 μM) for 1 hour before adding 2’3’-cGAMP (30 μM) and  cAIM(PS)2 Difluor (Rp/Sp) (10 μM). After overnight incubation, activation of the IRF pathway was assessed by measuring Lucia luciferase activity in the supernatant, using the QUANTI‑Luc™ detection reagent. Data are shown as a percentage (%) inhibition of the maximal response for the ligand with no BFA.

Brefeldin A inhibits constitutively activated STING in THP1-Dual™ KI-hSTING-S154 cells: The cells were incubated in the presence or absence of increasing concentrations of Brefeldin A (0 ‑ 10 μM) for 18 hours. Inhibition of STING-induced signaling was assessed by measuring the activity of the constitutively expressed Lucia luciferase in the supernatant, using the QUANTI‑Luc™ detection reagent. Data are shown as a percentage (%) inhibition of the maximal response of the cell line with no BFA.

Specifications

CAS number: 20350-15-6

Solubility: 10 mg/ml in DMSO

Working concentration:  1 - 10 μM for InvivoGen's cell culture assays

Formula: C₁₆H₂₄O₄ 

Molecular weight: 280.36 g/mol

Quality control:

• Purity: ≥95% (UHPLC)
• Inhibition of the STING-induced IRF pathway by Brefeldin A has been confirmed using cellular assays.
• The absence of bacterial contamination (e.g. lipoproteins and endotoxins) has been confirmed using HEK-Blue™ TLR2 and HEK-Blue™ TLR4 cells.

Contents

Brefeldin A is provided as an evaporated translucent film. It is available in two quantities:

• inh-bfa: 10 mg
• inh-bfa-2: 2 x 10 mg

Brefeldin A  is shipped at room temperature.

Upon receipt, store at -20 °C. 

Details

Chemical structure of Brefeldin A: