TY - JOUR T1 - Mutation of the Galectin-3 Glycan Binding Domain (<em>Lgals3</em>-R200S) Enhances Cortical Bone Expansion in Male and Trabecular Bone Mass in Female Mice JF - bioRxiv DO - 10.1101/2020.01.09.900787 SP - 2020.01.09.900787 AU - Kevin A. Maupin AU - Daniel Dick AU - VARI Vivarium AU - Transgenics Core AU - Bart O. Williams Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/01/09/2020.01.09.900787.abstract N2 - The study of galectin-3 is complicated by its ability to function both intracellularly and extracellularly. While the mechanism of galectin-3 secretion is unclear, studies have shown that the mutation of a highly conserved arginine to a serine in human galectin-3 (LGALS3-R186S) blocks glycan binding and secretion. To gain insight into the roles of extracellular and intracellular functions of galectin-3, we generated mice with the equivalent mutation (Lgals3-R200S) using CRISPR/Cas9-directed homologous recombination. Consistent with a reduction in galectin-3 secretion, we observed significantly reduced galectin-3 protein levels in the plasma of heterozygous and homozygous mutant mice. We observed a similar increased bone mass phenotype in Lgals3-R200S mutant mice at 36 weeks as we previously observed in Lgals3-KO mice with slight variation. Like Lgals3-KO mice, Lgals3-R200S females, but not males, had significantly increased trabecular bone mass. However, only male Lgals3-R200S mice showed increased cortical bone expansion, which we had previously observed in both male and female Lgals3-KO mice and only in female mice using a separate Lgals3 null allele (Lgals3). These results suggest that the trabecular bone phenotype of Lgals3-KO mice was driven primarily by loss of extracellular galectin-3. However, the cortical bone phenotype of Lgals3-KO mice may have also been influenced by loss of intracellular galectin-3. Future analyses of these mice will aid in identifying the cellular and molecular mechanisms that contribute to the Lgals3-deficient bone phenotype as well as aid in distinguishing the extracellular vs. intracellular roles of galectin-3 in various signaling pathways. ER -