Optineurin Shapes Basal and LPS-Induced Transcriptomes in BV2 Microglia

The OPTN gene is linked to neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), which are characterized by chronic microglial activation. Optineurin regulates inflammatory signaling, autophagy, and trafficking, but its role in microglia is not well understood. We used bulk RNA sequencing to profile CRISPR-Cas9-mediated optineurin knockout (KO) and wild-type (WT) BV2 microglia under basal conditions and upon LPS stimulation. At baseline, optineurin KO altered approximately 7% of the transcriptome, with a notable downregulation of type I interferon and antiviral pathways. LPS stimulation in wild-type cells triggered a broad transcriptional shift (~35% of genes). This LPS-induced response was blunted in optineurin-deficient microglia, with ~16% of genes changed relative to the KO baseline. Furthermore, LPS-treated optineurin KO microglia notably diverged from LPS-treated wild-type cells, with ~26% differentially expressed genes. Our findings establish optineurin as a key regulator of the microglial transcriptome. Its loss weakens basal interferon-mediated immune surveillance and decouples the canonical inflammatory response from cell cycle arrest upon activation.