Alternative Splicing as a Modulator of the Interferon-Gamma Pathway.

Interferon-gamma (IFN-γ) is a critical cytokine that plays a pivotal role in immune system regulation. It is a key mediator of both cellular defense mechanisms and antitumor immunity. As the sole member of the type II interferon family, IFN-γ modulates immune responses by activating macrophages, enhancing natural killer cell function, and regulating gene expression across multiple cellular processes. Alternative splicing is a post-transcriptional gene expression regulatory mechanism that generates multiple mature messenger RNAs from a single gene, dramatically increasing proteome diversity without the need of a proportional genome expansion. This process occurs in 90-95% of human genes, with alternative splicing events allowing for the production of diverse protein isoforms that can have distinct-or even opposing-functional properties. Alternative splicing plays a crucial role in cancer immunology, potentially generating tumor neoepitopes and modulating immune responses. However, how alternative splicing affects IFN-γ's activity is still poorly understood. This review explores how alternative splicing regulates the expression and function of both upstream regulators and downstream effectors of IFN-γ, revealing complex mechanisms of gene expression and immune response modulation. Key transcription factors and signaling molecules of the IFN-γ pathway are alternatively spliced, and alternative splicing can dramatically alter IFN-γ signaling, immune cell function, and response to environmental cues. Specific splice variants can enhance or inhibit IFN-γ-mediated immune responses, potentially influencing cancer immunotherapy, autoimmune conditions, and infectious disease outcomes. The emerging understanding of these splicing events offers promising therapeutic strategies for manipulating immune responses through targeted molecular interventions.