Galectin-8 Protein Regulates CD44v Localization and Limits STAT3 Signaling in Gastric Metaplasia
A new preprint study using a mouse model of gastric metaplasia found that the protein galectin-8 is required for proper membrane localization of CD44 variant proteins and suppresses downstream STAT3 signaling. Researchers compared mice lacking the Lgals8 gene to normal mice in a chemically induced model of spasmolytic polypeptide-expressing metaplasia (SPEM), observing increased nuclear pSTAT3 in the knockout animals. These findings may help explain why low galectin-8 expression is clinically associated with worse outcomes in gastric cancer patients.
Researchers posting to bioRxiv report that galectin-8, a lectin with preference for sialylated and sulfated sugar modifications, plays a regulatory role in gastric metaplasia by anchoring CD44 variant proteins (CD44v) to the cell membrane and restraining STAT3 signaling. The study used a synchronous, chemically induced murine model that generates gastric spasmolytic polypeptide-expressing metaplasia (SPEM), comparing Lgals8 knockout mice to wild-type C57BL/6J controls. In the absence of galectin-8, CD44v failed to localize properly to the membrane of SPEM cells at the base of gastric glands, suggesting a direct physical interaction between the two proteins. Metaplastic glands from knockout mice also showed elevated nuclear phospho-STAT3, indicating that galectin-8 normally tempers the CD44-to-STAT3 signaling axis. Because CD44v proteins specifically express 3'-Sialyl-LeA/X glycotopes — the preferred binding targets of galectin-8 — the interaction appears biochemically specific. The authors propose that these mechanistic findings provide a potential explanation for the previously observed clinical correlation between low galectin-8 expression and poorer prognosis in gastric cancer.
What's missing
As a preprint, this work has not yet undergone peer review. The study is limited to a chemically induced mouse model, and it is unclear whether the findings translate to human gastric metaplasia or cancer. The authors do not address whether galectin-8 loss is sufficient to drive malignant progression or whether STAT3 hyperactivation in this context has functional consequences for tumor development. The mechanism of physical interaction between galectin-8 and CD44v has not been directly demonstrated (e.g., via co-immunoprecipitation or structural data).
What different sources said
- bioRxivCenter
Galectin-8 Modulates Membrane CD44v Localization and Tempers STAT3 Signaling in Gastric Metaplasia
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