ag-490 and Lupus-Erythematosus--Systemic

Mesenchymal stem cells (MSCs) derived from patients with systemic lupus erythematosus (SLE) exhibit enhanced senescence. Cellular senescence has been reported to be induced by several inflammatory cytokines, including interferon-α (IFNα) and IFNγ, that are involved in the pathogenesis of SLE. We undertook this study to investigate whether the inflammatory environment in SLE could affect MSC senescence.. Cellular senescence was measured by staining of senescence-associated β-galactosidase and by expression of the cell cycle inhibitors p53 and p21. Eighty cytokines and chemokines in serum from healthy controls and patients with SLE were identified by cytokine antibody array.. SLE serum promoted senescence of MSCs, which was reversed by the phosphatidylinositol 3-kinase (PI3K)/Akt signaling inhibitor LY294002 but not by the JAK/STAT inhibitor AG490 and not by the MEK/ERK inhibitor PD98059. Cytokine antibody array analysis revealed that leptin and neutrophil-activating peptide 2 (NAP-2) were the 2 factors most significantly elevated in SLE serum compared with normal serum. Blockade of leptin or NAP-2 in MSC cultures abolished SLE serum-induced senescence, while direct addition of these 2 factors could promote senescence in cultures of normal MSCs. Inhibition of PI3K/Akt signaling with LY294002 reduced leptin- and NAP-2-induced senescence in MSCs.. Taken together, our data show that leptin and NAP-2 act synergistically to promote MSC senescence through enhancement of the PI3K/Akt signaling pathway in SLE patients.

Topics: Adult; Case-Control Studies; Cellular Senescence; Chromones; Cytokines; Enzyme Inhibitors; Female; Flavonoids; Humans; Janus Kinases; Leptin; Lupus Erythematosus, Systemic; MAP Kinase Signaling System; Mesenchymal Stem Cells; Morpholines; Peptides; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; STAT Transcription Factors; Tyrphostins; Young Adult

Estrogen-mediated regulation of Th1, Th2 and Treg effector functions are well documented but, surprisingly, there is little information whether estrogen modulates IL-17, a powerful proinflammatory cytokine that plays a pivotal role in several inflammatory and autoimmune diseases. Therefore in the current study, we determined whether estrogen regulates the expression levels of IL-17 in WT C57BL/6 mice. By ELISA, ELISPOT and/or flow cytometric analyses, we found that estrogen upregulated the levels of not only IL-17, but also the IL-17-specific transcription factor retinoic acid-related orphan receptor gamma t (ROR gamma t), in activated splenocytes. IL-17 levels were further enhanced by exposure of activated splenocytes to IL-23, particularly in cells from estrogen-treated mice. Exposure of splenocytes to IL-27 or IFN-gamma at the time of activation markedly inhibited the levels of IL-17 and ROR gamma t. Interestingly, a delay of 24 h in exposure of activated splenocytes to IL-27 or IFN-gamma decreased IL-17 levels (albeit less profoundly) but not ROR gamma t. These findings imply that the suppressive effects of IL-27 and IFN-gamma are more effective prior to the differentiation and commitment of IL-17-secreting cells. Furthermore, inhibition of JAK-2 by AG490 suppressed IL-17 but not ROR gamma t expression, suggesting that other transcription factors are also critical in estrogen-mediated upregulation of IL-17.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Estrogens; Female; Gene Expression Regulation; Humans; Interferon-gamma; Interleukin-17; Interleukin-23; Interleukins; Janus Kinase 2; Lupus Erythematosus, Systemic; Male; Mice; Mice, Inbred C57BL; Mice, Inbred NZB; Nuclear Receptor Subfamily 1, Group F, Member 3; T-Lymphocytes, Helper-Inducer; Tyrphostins