Nano-SiO2

Inflammasome activation with Nano-SiO₂

NLRP3 Inflammasome Inducer

SiO₂ nanoparticles (Nano-SiO₂) are single particles of silica dioxide, an inorganic metal oxide, with a diameter of less than 100 nm. Several studies have demonstrated that Nano-SiO₂ triggers interleukin-1β (IL-1β) secretion in vitro and in vivo [1, 2]. IL-1β is produced as a pro-protein which is proteolytically processed to its active form by caspase-1. The secretion of IL-1β is an indicator of the NLRP3 inflammasome induction.

The NLRP3 inflammasome is an intracellular multi-protein complex that plays a central role in innate immunity [3, 4]. It is activated by a two-step process; a first signal (‘priming’) is provided by microbial molecules such as lipopolysaccharide (LPS), while the second signal is provided by a wide array of stimuli including bacterial toxins, endogenous molecules, crystals or nanoparticles such as Nano-SiO₂. This triggers inflammasome multimerization and caspase-1 activation with the subsequent maturation and secretion of IL-1β and IL-18. Research has confirmed that the IL-1β secretion and pro-inflammatory activity of Nano-SiO₂ are mediated by the NLRP3 inflammasome [1, 2].

InvivoGen’s Nano-SiO₂ is designed for in vitro assays. Its ability to induce the NLRP3 inflammasome has been validated using THP-1 Null cells.

Features of Nano-SiO₂:

• Potent inducer of the NLRP3 inflammasome
• Nanoparticles with a diameter of <100 nm
• Each lot is functionally tested

Read our review on NLRP3 inflammasome

References:

1. Nakayama M. et al., 2018. Macrophage recognition of crystals and nanoparticles. Front Immunol. 9:103. 
2. He Y. et al., 2016. NEK7 is an essential mediator of NLRP3 activation downstream of potassium efflux. Nature. 530(7590):354-7.
3. Li H. et al., 2008. Cutting Edge: Inflammasome activation by Alum and Alum’s adjuvant effect are mediated by NLRP3. J Immunol. 181:17-21.
4. Hornung V. et al., 2008. Silica crystals and aluminium salts activate the NALP3 inflammasome through phagosomal destabilization. Nature Immunol. 9:847-856.

Figures

IL-1β production in THP1-Null cells.

THP1-Null cells, primed with LPS (1 µg/ml for 3h), were stimulated with increasing concentrations of Nano-SiO₂. After overnight incubation,  IL-1β secretion was analyzed by adding 50  µl of supernatant from treated THP1-Null cells to HEK-Blue™ IL-1β cells. IL-1β-induced activation of NF-κB was assessed by measuring the levels of SEAP in the supernatant of HEK-Blue™ IL-1β cells using QUANTI-Blue™ Solution, a SEAP detection reagent, and by reading the optical density (OD) at 630 nm.

Specifications

Working concentration: 10-250 µg/ml

CAS number: 7631-86-9

Linear formula: SiO₂

Molecular weight: 60.08 g/mol

Contents

• 20 mg (2 x 10 mg) Nano-SiO2 (nanoparticles of silica dioxide)

Nano-SiO2 is shipped at room temperature.

Store at room temperature.

Details

THP-1/HEK-Blue™ IL-1β Assay

Nano-SiO₂ can be used to induce the NLRP3 inflammasome in cellular assays, such as InvivoGen’s THP1/HEK-Blue™ IL-1β assay. This assay uses the secretion of IL-1β by THP1-Null cells as an indicator of NLRP3 inflammasome induction. The production IL-1β by these cells is measured using HEK-Blue™ IL-1β cells.

1- Production of IL-1β by THP-1 cells: Typically, THP1-Null cells are primed with lipopolysaccharide (LPS). This treatment induces the production of NLRP3 and pro-IL-1β, the immature form of IL-1β. Subsequent stimulation with inflammasome inducers, such as Nano-SiO₂, leads to NRLP3 and caspase-1 activation resulting in IL-1β maturation and secretion.

2- Detection of IL-1β by HEK-Blue™ IL-1β cells: THP1-Null cell supernatants containing IL-1β can be added to HEK-Blue™ IL-1β cells. This activates NF-κB and leads to the subsequent production of secreted embryonic alkaline phosphatase (SEAP). The presence of SEAP in HEK-Blue™ IL-1β supernatants is assessed using QUANTI-Blue™ Solution, a SEAP detection medium.