Glucosamine inhibits IL-1\u03b2 expression by preserving mitochondrial integrity and disrupting assembly of the NLRP3 inflammasome

Hsiao-Wen Chiu,Kuo-Feng Hua,Ann Chen,Chih-Yu Hsieh,Fang-Hsin Chen,Yerra Koteswara Rao,Shuk-Man Ka,Lan-Hui Li

doi:10.1038/s41598-019-42130-z

Abstract

The NLRP3 inflammasome promotes the pathogenesis of metabolic, neurodegenerative and infectious diseases. Increasing evidences show that the NLRP3 inflammasome is a promising therapeutic target in inflammatory diseases. Glucosamine is widely used as a dietary supplement to promote the health of cartilage tissue and is expected to exert anti-inflammatory activity in joint inflammation, which is a nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome-associated complication. Here, we investigated whether GlcN inhibits the NLRP3 inflammasome and dissected the underlying molecular mechanisms. We found that GlcN suppressed the NLRP3 inflammasome in mouse and human macrophages. A mechanistic study revealed that GlcN inhibited the expression of NLRP3 and IL-1β precursor by reducing reactive oxygen species generation and NF-κB activation in lipopolysaccharide-activated macrophages. GlcN also suppressed mitochondrial reactive oxygen species generation and mitochondrial integrity loss in NLRP3-activated macrophages. Additionally, GlcN disrupted NLRP3 inflammasome assembly by inhibiting NLRP3 binding to PKR, NEK7 and ASC. Furthermore, oral administration of GlcN reduced peritoneal neutrophils influx and lavage fluids concentrations of IL-1β, IL-6 MCP-1 and TNF-α in uric acid crystal-injected mice. These results indicated that GlcN might be a novel dietary supplement for the amelioration of NLRP3 inflammasome-associated complications.

Highlights

The nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome is a protein complex composed of NLRP3, apoptosis-associated speck-like protein containing CARD domain (ASC) and caspase-1 that controls the release of the pro-inflammatory cytokines IL-1β and IL-181
We found that glucosamine hydrochloride (GlcN) (10 and 30 mM) significantly inhibited IL-1β secretion induced by ATP, nigericin, monosodium urate crystals (MSU) and E. coli infection (Fig. 1A)
We found that GlcN significantly reduced IL-1β expression levels in the culture medium (Fig. 1F), indicating that the inhibitory effect of GlcN on IL-1β secretion was not specific to LPS priming only

Summary

Introduction

The nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome is a protein complex composed of NLRP3, apoptosis-associated speck-like protein containing CARD domain (ASC) and caspase-1 that controls the release of the pro-inflammatory cytokines IL-1β and IL-181. *, *** and **** indicate a significant difference at the level of p < 0.05, p < 0.001 and p < 0.0001, respectively, compared to NLRP3 activator-treated cells. In addition to its joint-protective effects, glucosamine exerts anti-inflammatory activities and ameliorates inflammatory diseases. Glucosamine exerts in vivo anti-inflammatory effects because it ameliorates brain inflammation[11], inflammatory bowel disease[13], lung inflammation[14], atherosclerosis[15], experimental autoimmune encephalomyelitis[16] and renal fibrosis[17]. Because glucosamine ameliorates NLRP3-associated inflammatory diseases, we hypothesize that the protective effects of glucosamine may be associated with its anti-NLRP3 inflammasome activity. We investigated whether GlcN inhibits the NLRP3 inflammasome and dissected the underlying molecular mechanisms in macrophages and in a NLRP3-associated mouse disease model

Methods

Results

Conclusion