Disease-associated mutations in CIAS1 induce cathepsin B–dependent rapid cell death of human THP-1 monocytic cells

Abstract

Mutations in the cold-induced autoinflammatory syndrome 1 (CIAS1) gene are associated with a spectrum of autoinflammatory diseases, including familial cold autoinflammatory syndrome, MuckleWells syndrome, and chronic infantile neurologic, cutaneous, articular syndrome, also known as neonatal-onset multisystem inflammatory disease. CIAS1 encodes cryopyrin, a protein that localizes to the cytosol and functions as pattern recognition receptor. Cryopyrin also participates in nuclear factor-B regulation and caspase-1-mediated maturation of interleukin 1␤. In this study, we showed that disease-associated mutations in CIAS1 induced rapid cell death of THP-1 monocytic cells. The features of cell death, including 7-AAD staining, the presence of cellular edema, and early membrane damage resulting in lactate dehydrogenase (LDH) release, indicated that it was more likely to be necrosis than apoptosis, and was effectively blocked with the cathepsin B-specific inhibitor CA-074-Me. CA-074-Me also suppressed induced by disease-associated mutation lysosomal leakage and mitochondrial damage. In addition, R837, a recently identified activator of cryopyrin-associated inflammasomes, induced cell death in wild type CIAS1-transfected THP-1 cells. These results indicated that monocytes undergo rapid cell death in a cathepsin B-dependent manner upon activation of cryopyrin, which is also a specific phenomenon induced by disease-associated mutation of CIAS1. IntroductionChronic infantile neurologic, cutaneous, articular syndrome (CINCA; MIM #697115; Mendelian Inheritance in Man [MIM]; http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?dbϭOMIM), also known as neonatal-onset multisystem inflammatory disease, is characterized by recurrent fever, an urticarial rash beginning in the neonatal period, arthropathy characterized by epiphyseal patellar overgrowth, growth retardation, chronic meningitis, papilledema, and hearing loss. 1,2 The gene responsible for the syndrome is known as cold-induced autoinflammatory syndrome 1 (CIAS1), and is associated with 2 less severe but phenotypically similar syndromes, familial cold autoinflammatory syndrome (FCAS; MIM #120100) and Muckle-Wells syndrome (MWS; MIM #191900). 3-7 CIAS1, also designated as PYPAF1 and NALP3, is expressed in polymorphonuclear cells, monocytes, chondrocytes, and activated T cells. 6,8,9 Its product is cryopyrin, which contains an amino-terminal pyrin domain (PYD), a centrally located nucleotidebinding oligomerization domain (NOD), also called a NACHT domain, and several carboxy-terminal leucine-rich repeats (LRRs). Cryopyrin localizes to the cytosol and is believed to function as a patternrecognition receptor.Animals and plants have several types of so-called patternrecognition receptors that distinguish characteristic molecular structures of microorganisms and activate innate immune responses. In mammals, Toll-like receptors (TLRs) are a wellcharacterized type of pattern-recognition receptor that recognize pathogen-associated molecular patterns via their extracellular LRRs. 10 Cryopy...

The inflammasomes in health and disease: from genetics to molecular mechanisms of autoinflammation and beyond

“…LPS-treated monocytes expressing the Y570C mutation showed an increased necrotic-like cell death associated with lysosomal leakage and other cellular metabolic alterations. 80,81 Moreover, monocytes transfected with Y570C exhibited higher NF-kB activity compared to healthy controls. 82,83 A second important aspect is that some CINCA patients with milder symptoms apparently lack NLRP3 mutations but carry a latent lowlevel mosaicism.…”

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“…Patient cells spontaneously released IL-1β in response to incubation at 32°C, a result that was blocked by anakinra, and that confirmed that modest cold exposure can trigger IL-1β release in these patients [21]. The role of mutant CIAS1-induced necrosis described in an in-vitro model needs further evaluation [22].…”

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“…In the first report by Barton et al (1), the IVIG infusion was followed by a decrease in IgG and IgM serum levels within 72 hours, and a typical biopsy-proved cryoglobulinemic membranoproliferative glomerulonephritis. In a case described by Odum et al (2), IVIG infusion was followed within 48 hours by diffuse purpura, a rise in plasma creatinine levels, a microscopic hematuria, and high-level proteinuria strongly suggestive of glomerulonephritis. Yebra et al reported a flare of hepatitis C virus-related cryoglobulinemic vasculitis 4 hours after the first IVIG infusion, an increase of cryoglobulin precipitation, and depletion of the monoclonal IgM after in vitro addition of IVIG, and suggested that this simple method could help to predict the risk of cryoglobulin-IVIG immune complex formation and should be performed before starting IVIG in patients with mixed cryoglobulinemia (3).…”