Human monocytes/macrophages (M/MΦ) of the innate immunity sense and respond to microbial products via specific receptor coupling with stimulatory (such as TLR) and inhibitory (such as Tim-3) receptors. Current models imply that Tim-3 expression on M/MØ can deliver negative signaling to TLR-mediated IL-12 expression through trans association with its ligand Galectin-9 (Gal-9) presented by other cells. However, Gal-9 is also expressed within M/MØ, and the effect of intracellular Gal-9 on Tim-3 activities and inflammatory responses in the same M/MØ remains unknown. In this study, our data suggest that Tim-3 and IL-12/IL-23 gene transcriptions are regulated by enhanced or silenced Gal-9 expression within monocytes through synergizing with TLR signaling. Additionally, TLR activation facilitates Gal-9/Tim-3 cis association within the same M/MØ to differentially regulate IL-12/IL-23 expressions through STAT-3 phosphorylation. These results reveal a ligand (Gal-9) compartment-dependent regulatory effect on receptor (Tim-3) activities and inflammatory responses via TLR pathways-a novel mechanism underlying cellular responses to external or internal cues.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-16012 |
| Date | 14 August 2013 |
| Creators | Ma, Cheng J., Li, Guang Y., Cheng, Yong Q., Wang, Jia M., Ying, Ruo S., Shi, Lei, Wu, Xiao Y., Niki, Toshiro, Hirashima, Mitsumi, Li, Chuan F., Moorman, Jonathan P., Yao, Zhi Q. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | ETSU Faculty Works |
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