IL‐10 modulates cytokine gene transcription by protein synthesis‐independent and dependent mechanisms in lipopolysaccharide‐treated neutrophils

Abstract

We have recently reported that the ability of IL-10 to rapidly exert its anti-inflammatory effects on human neutrophils is dependent upon exposure of these cells to LPS for at least 3-4 h. Here, we demonstrate that, in neutrophils "preconditioned" by LPS, IL-10 primarily targets the transcription of TNF-a, CXCL8 and IL-1ra genes, as revealed by primary transcript real-time RT-PCR. We also show that IL-10-induced transcriptional repression of TNF-a and CXCL8 genes consists of two distinct phases: an early one, occurring rapidly and in a protein synthesis-independent manner, followed by a second phase, more delayed and dependent on protein synthesis. Interestingly, the protein synthesis dependence of the latter phase coincides with a reduced ability of IL-10 to induce STAT3 tyrosine phosphorylation. Importantly, inhibition of IL-10-induced STAT3 activation and IL-10-suppressive action by a prolonged exposure to cycloheximide (CHX) was observed to occur also in human monocytes and was caused by a defective IL-10-mediated activation of Jak1 and Tyk2 kinases. Taken together, our findings suggest that CHX interferes with the IL-10-mediated intracellular signaling pathway by interrupting events upstream of STAT3 activation. These data question the concept of the requirement of an IL-10-induced mediator as the unique mechanism to execute IL-10 anti-inflammatory program.

Urine cytokines suggest an inflammatory response in the overactive bladder: a pilot study

“…T H 2 infiltration may be indicated by the presence of IL-10 and IL-5 in urine of OAB patients. Given that elevated IL-10 is a hallmark of inflammation induced by sterile trauma [24], our results point to this mechanism, as well as a possible compensatory response to tissue inflammation [25,26] in OAB. The finding of elevated IL-5, a T H 2 cytokine, further suggests a possible eosinophilic infiltration, which has been reported in the neurogenic bladder of spinal cord injury patients [9].…”

Biology of interleukin-10

“…There is however general agreement that STAT3 activation by IL-10 receptor engagement is New protein synthesis induced by STAT3 activation seems to be necessary for the antiinflammatory effects of IL-10 in myeloid cells although anti-inflammatory effects independent of new protein synthesis have been described in neutrophils (165). This prompted several studies on identifying genes which are induced by IL-10 by gene profiling (114,166,167).…”

Genome-wide analysis of STAT3 binding in vivo predicts effectors of the anti-inflammatory response in macrophages

“…Although it is known that STAT3 translocates to the nucleus within seconds on IL-10 stimulation, 51 sustained protein synthesis is needed to maintain a prolonged and effective AIR, as shown in mouse and human macrophages, 30,52 as well as in human monocytes and neutrophils. 53 Because the major effectors of the AIR have not yet been found, we predicted a set of putative STAT3 targets that might be involved in executing the AIR. We identified 351 genes that are up-regulated and possess a STAT3-binding site (within 20 kb of their TSS), of which 45 are predicted TFs.…”