Cryo-sensitive aggregation triggers NLRP3 inflammasome assembly in cryopyrin-associated periodic syndrome

SummaryCryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory syndrome caused by mutations of NLRP3, which was originally identified as cryopyrin. Familial cold autoinflammatory syndrome (FCAS), the mildest form of CAPS, is characterized by cold-induced inflammation induced by the overproduction of IL-1β. However, the molecular mechanism of how mutated NLRP3 causes inflammasome activation in CAPS remains unclear. Here, we found that CAPS-associated NLRP3 mutants form cryo-sensitive aggregates that function as a scaffold for inflammasome activation. Cold exposure promoted inflammasome assembly and subsequent IL-1β release triggered by mutated NLRP3. While K+ efflux was dispensable, Ca2+ was indispensable for mutated NLRP3-mediated inflammasome assembly. Notably, Ca2+ influx was induced during mutated NLRP3-mediated inflammasome assembly. Furthermore, caspase-1 inhibition prevented Ca2+ influx and inflammasome assembly induced by the mutated NLRP3, suggesting a feed-forward Ca2+ influx loop triggered by mutated NLRP3. Thus, the mutated NLRP3 forms cryo-sensitive aggregates to promote inflammasome assembly distinct from canonical NLRP3 inflammasome activation.

Cryopyrin-Associated Periodic Syndromes and Treatment Options

Cryopyrin-associated periodic syndromes (CAPSs) are a growing family of autoinflammatory diseases, also known as periodic fever syndromes. There are three forms of CAPS: (1) Familial Cold autoinflammatory syndrome or familial cold urticaria, (2) Muckle-wells syndrome, and (3) neonatal-onset multisystem inflammatory disease or chronic infantile neurological cutaneous articular syndrome. Genetic mutations in the NLRP3 gene were found to be present in most patients. The foremost common findings between all the CAPS disorders are rash, fever which is sometimes present at birth or in early childhood, joint problems, and conjunctivitis. More extreme forms of CAPS include more persistent inflammation that can cause hearing loss and meningitis and can lead to mental and developmental delays. Drugs for CAPS target the source of inflammation – which is the over-production of interleukin 1ß by modified cryopyrin inflammasomes. Three drugs are used to treat CAPS: Rilonacept, canakinumab, and anakirna. With these drugs, the prognosis is greatly improved, with most patients having less frequent episodes, decreased buildup of amyloid in the body, and extended life of severe cases up to adulthood.

Recognising and understanding cryopyrin-associated periodic syndrome in adults

Cryopyrin-associated periodic syndrome (CAPS) is a group of rare hereditary autoinflammatory diseases characterised by recurrent flares of mild to severe systemic inflammation and fever. CAPS is the umbrella term for a spectrum of individual conditions, namely familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and neonatal-onset multisystem inflammatory disease (NOMID), also known as chronic infantile neurologic, cutaneous and articular (CINCA) syndrome. The flare symptoms include fever, fatigue, rashes, headaches, arthralgia and myalgia that can last for a few hours or for several days. These symptoms are debilitating, contributing to poor quality of life for patients if left untreated. Serious life-changing complications such as hearing loss, blindness and AA amyloidosis resulting in kidney failure can occur. Until recently, treatment of the disease was symptomatic using non-steroidal anti-inflammatory and immunosuppressant drugs with limited success. In contrast, biological treatments targeting interleukin 1 (IL-1) have proved remarkably effective, often associated with complete and sustained disease remission, vastly improved quality of life and avoidance of serious long-term complications.

Criopirinopatías: ¿qué son?, ¿cómo detectarlas? y ¿cuál es el enfoque de su tratamiento?

Los síndromes periódicos asociados con criopirinas (Cryopyrin Associated Periodic Syndromes, CAPS), o criopirinopatías, son enfermedades raras que hacen parte de los síndromes autoinflamatorios, caracterizados por episodios de fiebre recu­rrente e inflamación sin etiología autoinmunitaria, neoplásica ni infecciosa. Entre estos síndromes, los CAPS incluyen tres entidades: el síndrome autoinflamatorio familiar por frío (Familial Cold Autoinflammatory Syndrome, FCAS), el síndrome de Muckle-Wells y la enfermedad multisistémica inflamatoria de inicio neonatal (Neonatal Onset Multisystem Inflammatory Disease, NOMID), también conocida como síndrome articular, cutáneo y neurológico crónico infantil (Chronic Infantile Neurological Cutaneous and Articular (CINCA) syndrome). Se han identificado mutaciones en el gen NLRP3 como etiología de estos sín­dromes, con un patrón de herencia autosómico dominante en la mayoría de los casos. El diagnóstico suele hacerse por sus manifestaciones clínicas, con apoyo de la biopsia de piel, y se confirma con el estudio genético. Hasta la fecha, el tra­tamiento basado en el bloqueo de la IL-1β, ha mostrado una mejoría satisfactoria en la mayoría de los pacientes.