Fasl Knockout RAW 264.7 Cell Line

The Fasl Knockout RAW 264.7 Cell Line is a CRISPR/Cas9-edited knockout cell line derived from the murine RAW 264.7 macrophage line, featuring targeted disruption of the Fasl gene. This engineered cell model provides a reliable loss-of-function tool for investigating Fas ligand (FasL)-mediated biological processes in a macrophage context.

RAW 264.7 is an extensively characterized Abelson murine leukemia virus-transformed mouse macrophage cell line originating from BALB/c mice. These cells exhibit robust phagocytic activity, produce a broad array of pro-inflammatory cytokines, and are widely employed as a model for innate immune responses, including inflammation, host-pathogen interactions, and immunomodulatory compound screening.

FasL (CD95L) is a type II transmembrane protein that triggers apoptosis by binding to its cognate receptor Fas (CD95). Upon ligand engagement, Fas recruits the adaptor protein FADD and procaspase-8 to form the death-inducing signaling complex (DISC), which leads to caspase-8 activation and subsequent cleavage of executioner caspases such as caspase-3 and PARP, culminating in apoptotic cell death. This extrinsic apoptosis pathway is tightly regulated by factors including NF-??B, AP-1, and c-FLIP. FasL expression is transcriptionally upregulated by LPS, IFN-??, and TCR signaling through NF-??B and AP-1. Downstream of FasL, the activated caspase cascade intersects with additional signaling modules, including NF-??B, JNK, and p38 MAPK, thereby influencing both apoptotic and non-apoptotic cellular outcomes. The decoy receptor DcR3 can competitively bind FasL, providing a negative regulatory mechanism.

In the RAW 264.7 macrophage background, FasL contributes to immune regulatory functions, including induction of apoptosis in target cells and modulation of pro-inflammatory responses. Macrophages express FasL upon activation, and its signaling can influence both autocrine and paracrine death pathways, impacting tissue homeostasis and inflammation. The knockout of Fasl in this cell line eliminates FasL-mediated effects, enabling researchers to dissect the role of macrophage-derived FasL in processes such as T cell regulation, tumor cell killing, and cytokine-driven inflammation.

This knockout cell line is a versatile platform for investigating FasL-dependent apoptosis in macrophages, the interplay between death receptor signaling and innate immune activation, and the pathogenesis of autoimmune disorders, graft-versus-host disease, and inflammatory diseases. Researchers can employ a range of assays including western blotting for FasL and cleaved caspase-3, RT-qPCR, flow cytometry for FasL surface expression, Annexin V/PI apoptosis assays, caspase-8 activity measurements, co-culture killing assays, and cytokine quantification via ELISA for TNF-?? and IL-6. For additional information, technical support, or custom gene-editing services, please contact Ascent Research.