The IFIH1 Knockout SH-SY5Y Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population in which the IFIH1 gene (MDA5) has been disrupted in the human SH-SY5Y neuroblastoma line. This loss-of-function model enables detailed investigation of MDA5-mediated innate immune pathways in a heterogeneous cellular background, avoiding clonal artifacts.
SH-SY5Y cells, derived from a bone marrow metastasis of a neuroblastoma patient, exhibit a dopaminergic neuronal phenotype and serve as a widely used neuronal model. Despite their cancerous origin, these cells retain functional pattern recognition receptor machinery, making them suitable for studying neuro-immune signaling and antiviral responses in a neural context.
IFIH1 encodes MDA5, a cytoplasmic sensor for long double-stranded RNA (dsRNA) from viral infections. Upon dsRNA binding, MDA5 recruits mitochondrial antiviral-signaling protein (MAVS), which assembles a signalosome containing TRAF3, TRAF6, TBK1, and IKK??. This complex phosphorylates IRF3 and activates NF-??B, leading to their nuclear translocation and transcription of type I interferons (e.g., IFN-??) and interferon-stimulated genes such as ISG15 and IFIT1. The scaffold 14-3-3 protein interacts with activated MDA5, further supporting signal transduction.
Gain-of-function IFIH1 mutations are implicated in Aicardi-Gouti??res syndrome and type I interferonopathies, characterized by chronic neuroinflammation. The IFIH1 knockout in SH-SY5Y cells offers a neuronal platform to dissect MDA5-specific contributions to innate immune activation, autoinflammatory processes, and host defense against neurotropic viruses, uncoupled from other RIG-I-like receptors.
Applications include innate immune profiling and antiviral response studies using RT-qPCR for IFN-?? and ISGs, western blotting for phospho-IRF3, immunofluorescence for IRF3 nuclear translocation, dual-luciferase reporter assays, and co-immunoprecipitation of MDA5-MAVS complexes. Viral infection assays with RNA viruses further validate functional outcomes. This model also supports drug screening for modulators of the RLR pathway. For further information, contact Ascent Research.
