Lgals9 Knockout NIH 3T3 Cell Line

The Lgals9 Knockout NIH 3T3 Cell Line is a CRISPR/Cas9-edited knockout cell line engineered to disrupt the murine Lgals9 gene encoding galectin-9. This cell line provides a loss-of-function model for studying galectin-9-dependent immune regulation, apoptosis, and cell adhesion in a mouse embryonic fibroblast background. The targeted gene disruption abolishes functional galectin-9 protein expression, enabling precise dissection of its role in signaling networks that govern T cell tolerance, inflammatory responses, and cellular survival pathways.

The host cell line, NIH 3T3, is a spontaneously immortalized embryonic fibroblast line derived from NIH Swiss mouse embryos. These cells are widely used in biomedical research due to their robust growth and ease of culture, providing a well-characterized model for studying signaling and adhesion. NIH 3T3 cells express key components of galectin-9-related pathways, including Tim-3 and CD44, making them a suitable platform for investigating galectin-9 function and its downstream effects.

Galectin-9, encoded by Lgals9, is a beta-galactoside-binding lectin that functions as a pivotal immune regulator. It interacts with T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3/HAVCR2) and CD44, triggering distinct intracellular cascades. Binding to Tim-3 on T cells activates caspase-dependent apoptosis, contributing to immune tolerance and suppression of effector responses. This interaction is modulated by upstream signals including interferon-gamma (IFN-??) and Toll-like receptor (TLR) ligands, which induce Lgals9 expression via NF-??B. Additionally, galectin-9 engagement with CD44 enhances cell adhesion and can influence mTOR and AMPK signaling, linking metabolism to adhesion and autophagy. The galectin-9/Tim-3 axis is a central checkpoint in T cell receptor signaling, while its CD44 interaction governs cell-matrix dynamics.

In NIH 3T3 fibroblasts, Lgals9 knockout disrupts the endogenous galectin-9 network, providing a clean background to study galectin-9-mediated adhesion and its crosstalk with intracellular signaling. These fibroblasts lack T cell-specific machinery but express CD44 receptors, allowing focused investigation of galectin-9/CD44-driven adhesion, spreading, and downstream pathways such as AMPK/mTOR regulation. The knockout model is particularly valuable for dissecting how galectin-9 contributes to fibroblast-mediated immune modulation, as NIH 3T3 cells can be co-cultured with T cells to examine paracrine or juxtacrine effects on apoptosis. This system also helps elucidate galectin-9’s role in extracellular matrix interactions and fibrotic responses under inflammatory conditions, as IFN-?? and NF-??B activity can be manipulated in vitro.

Researchers can employ this knockout cell line in a variety of advanced assays to explore galectin-9 biology. Flow cytometry enables quantification of apoptosis markers and surface expression of adhesion molecules like CD44 following stimulation with IFN-?? or TLR agonists. Western blotting and immunofluorescence facilitate analysis of downstream targets including cleaved caspases, phosphorylated mTOR, and AMPK activation status. Co-immunoprecipitation experiments can validate interactions with Tim-3 or CD44 when co-expressed. T cell apoptosis assays using co-culture systems allow functional assessment of galectin-9/Tim-3-mediated immune regulation. Cell adhesion and spreading assays provide quantitative measures of galectin-9’s role in fibroblast attachment. These applications support research in autoimmunity, cancer immunotherapy, chronic inflammation, and viral pathogenesis. For further information, please contact Ascent Research.