CD16 regulates TRIF-dependent TLR4 response in human monocytes and their subsets
| Autor: | Irina N. Shalova, Jyue Yuan Lim, Subhra K. Biswas, Francisco Arnalich, Philip Iau, Irene Fernández-Ruiz, Tasneem Kajiji, Vanesa Gómez-Piña, Siew Cheng Wong, Eduardo López-Collazo |
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| Rok vydání: | 2012 |
| Předmět: |
Adult
Immunology Primary Cell Culture Syk chemical and pharmacologic phenomena CD16 Biology Adaptive Immunity Transfection Monocytes Sepsis Mice Downregulation and upregulation immune system diseases medicine Immunology and Allergy CXCL10 Animals Humans Syk Kinase RNA Small Interfering Monocyte Receptors IgG Intracellular Signaling Peptides and Proteins virus diseases hemic and immune systems Middle Aged Protein-Tyrosine Kinases medicine.disease Endotoxins Mice Inbred C57BL Toll-Like Receptor 4 Adaptor Proteins Vesicular Transport medicine.anatomical_structure STAT1 Transcription Factor Gene Expression Regulation TRIF Myeloid Differentiation Factor 88 TLR4 Interferons Signal Transduction |
| Zdroj: | Journal of immunology (Baltimore, Md. : 1950). 188(8) |
| ISSN: | 1550-6606 |
| Popis: | Blood monocytes recognize Gram-negative bacteria through the TLR4, which signal via MyD88- and TRIF-dependent pathway to trigger an immune-inflammatory response. However, a dysregulated inflammatory response by these cells often leads to severe pathologies such as sepsis. We investigated the role of CD16 in the regulation of human monocyte response to Gram-negative endotoxin and sepsis. Blood monocytes from sepsis patients demonstrated an upregulation of several TRIF-dependent genes as well as a selective expansion of CD16-expressing (CD16+) monocytes. Gene expression and biochemical studies revealed CD16 to regulate the TRIF-dependent TLR4 pathway in monocytes by activating Syk, IFN regulatory factor 3, and STAT1, which resulted in enhanced expression of IFNB, CCL5, and CXCL10. CD16 also upregulated the expression of IL-1R–associated kinase M and IL-1 receptor antagonist, which are negative regulators of the MyD88-dependent pathway. CD16 overexpression or small interfering RNA knockdown in monocytes confirmed the above findings. Interestingly, these results were mirrored in the CD16+ monocyte subset isolated from sepsis patients, providing an in vivo confirmation to our findings. Collectively, the results from the current study demonstrate CD16 as a key regulator of the TRIF-dependent TLR4 pathway in human monocytes and their CD16-expressing subset, with implications in sepsis. |
| Databáze: | OpenAIRE |
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