Effects of Global O-G1cNAcylation on Galectin Gene-expression Profiles in Human Cancer Cell Lines
ANTICANCER RESEARCH
Authors: Sherazi, Ali A.; Jariwala, Komal A.; Cybulski, Amanda N.; Lewis, Justin W.; Karagiannis, Jim; Cumming, Robert C.; Timoshenko, Alexander V.
Abstract
Background/Aim: The effects of O-linked P-Nacetyl-D-glucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase (OGA) inhibitors on galectin gene expression profiles were examined in MCF7, HT-29, and HL-60 cancer cell lines. Materials and Methods: Cell cultures were treated for 24 h with OGA inhibitor thiamet G or OGT inhibitor 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-5-thio-a-D- glucopyranose, and global O-GlcNAc levels and expression of galectin genes were determined using an immunodot blot assay and real-time quantitative polymerase chain reaction. Results: Two galectin genes, LGALS3 in MCF7 cells and LGALSJ2 in HL-60 cells, were up-regulated by O-GlcNAc, whereas other cell-specific galectins were unresponsive to changes in O-GlcNAc level. Of interest, basal levels of O-GlcNAc in resting HL-60 and HT-29 cells were significantly higher than those in cells differentiated into neutrophilic or enterocytic lineages, respectively. Conclusion: O-GlcNAcmediated signaling pathways may be involved in regulating the expression of only a limited number of galectin genes. Additional O-GlcNAc-dependent mechanisms may work at the protein level (galectin secretion and intracellular localization) and warrant further investigation.
Macrophages and Galectin 3 Control Bacterial Burden in Acute and Subacute Murine Leptospirosis That Determines Chronic Kidney Fibrosis
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
Authors: Ferrer, Maria F.; Scharrig, Emilia; Charo, Nancy; Ripodas, Ana L.; Drut, Ricardo; Carrera Silva, Eugenio A.; Nagel, Ariel; Nally, Jarlath E.; Montes de Oca, Daniela P.; Schattner, Mirta; Gomez, Ricardo M.
Abstract
Previous studies have suggested that macrophages may contribute to acute Leptospira dissemination, as well as having a major role in kidney fibrosis. Our aim was to characterize the role of macrophages and galectin 3 (Gal-3) on the survival, clinical course, bacterial burden, interstitial nephritis, and chronic kidney fibrosis in Leptospira interrogans serovar Copenhageni (LIC)-induced experimental murine leptospirosis. C57BL/6J mice depleted of macrophages by liposome-encapsulated clodronate treatment and infected with LIC presented a higher bacterial burden, had reduced subacute nephritis and enhanced chronic kidney fibrosis relative to untreated, infected mice. Moreover, LIC infection in mice whose Gal-3 was disrupted (Lgals3(-/-)) had a higher bacterial burden and enhanced subacute nephritis and chronic kidney fibrosis when compared to C57BL/6J wild-type mice. Chronic fibrosis did not correlate with higher transcription levels of TGF-beta 1 or IL-13 in the kidneys. Kidney fibrosis was found in chronically infected rats as well as in wild infected rats. On the other hand, human fibroblast cultures exhibited enhanced differentiation to myofibroblasts after treatment with LIC. Our results demonstrate that macrophages and Gal-3 play a critical role in controlling the LIC burden but has a minor role in subsequent fibrosis. Instead, kidney fi brosis was better correlated with bacterial burden. Taken together, our results do not support a role for macrophages to disseminate leptospires during acute infection, nor in chronic kidney fi brosis.